1. Field of the Invention
The present invention relates to a resist composition which includes a fluorine-containing compound, a resist layer, an imprinting method, a pattern formation, a method for producing a magnetic recording medium, and a magnetic recording medium.
2. Description of the Related Art
In the field of storage media, much is expected from patterned media as a means for further improving performance.
Production methods of patterned media have been a problem, and methods utilizing nanoimprinting are regarded as popular in terms of fine shaping capability and productivity and are being examined in various ways.
Nanoimprinting is expected to be a method for securing a favorable balance between fine shaping capability and productivity.
It is presumed that nanoimprinting will be widely applied to the fields of semiconductors, devices, hard disks, optical films and so forth.
Especially in the fields of semiconductors and patterned media, for the purpose of further improving performance, nanoimprinting is highly expected to be utilized for patterning related to a region having a line width of 100 nm or less and a pattern aspect ratio of 2 or greater.
Also in these fields, since a surface on the side of a substrate is shaped by etching, using a formed pattern as a resist, in a step subsequent to pattern formation, it is necessary to reduce the thickness of a residual film formed, which is equivalent to the distance between the bottom of concave portions of the nanoimprint pattern and the substrate, for the purpose of further improving processing accuracy.
Further, it is necessary to achieve in-plane uniformity in the fine shaping, with respect to the entire imprint surface.
FIGS. 3A to 3C are schematic drawings exemplarily showing a conventional imprinting method which includes steps for forming a resist layer 102 (resist pattern) on a substrate 103 made of a material selected according to the purpose.
Firstly, a resist composition is applied onto the substrate 103 and then subjected to spin coating with a general-purpose spin coater (not shown) so as to form the resist layer 102. Secondly, a mold structure 110 on which a pattern for imprinting is formed is placed against the side of the resist layer 102 (see FIG. 3A). In this state, the mold structure 110 is pressed against the resist layer 102 so as to pattern the resist layer 102, with the pattern of the mold structure 110 serving as a template, then the mold structure 110 is separated from the resist layer 102 (see FIG. 3B). Thus, a resist pattern (resist layer 102) is formed on the substrate 103. At this time, a thin film of the resist layer 102 remains as a residual film 104 in gaps formed between convex portions of the mold structure and the substrate 103 with the resist layer 102 thereon (see FIG. 3C).
Various techniques for forming minute patterns in a highly productive manner have been proposed. For instance, there has been proposed a technique of making a fluorine-based compound present in a localized manner at the outermost surface of a resist layer and thus reducing adhesion or fixation of the resist to a mold structure, thereby improving patterning quality (refer to Japanese Patent Application Laid-Open (JP-A) Nos. 2005-159358 and 2006-310566).
Meanwhile, there has been proposed a technique of providing a layer (5 nm or less in thickness) of a fluorine compound on the surface of a resist so as to improve separability (refer to JP-A No. 2006-80447).
However, application of the technique to a minute pattern is difficult regarding the former example; and a pattern superior in minute shape can be obtained, but it is difficult to sufficiently reduce the thickness of a residual film owing to the viscosity of the resist composition regarding the latter example. Consequently, it is difficult to form an imprint pattern uniformly and with a small residual film thickness on the entire surface of a wide pattern area such as a HDD and thus to obtain a pattern with a uniform shape.